1. Field of the Invention
The present invention relates to a camera module, and more particularly, to a camera module in which a component for accommodating a lens and components installed on a substrate are integrally formed into one body to simplify a mold, to reduce design time, to reduce manufacturing costs of the mold and material costs, and to minimize volume of the camera module.
2. Description of the Related Art
Generally, a camera module includes a lens part containing a lens, a housing coupled with the lens part, and a sensor part including an IR filter, an image sensor, and the like.
FIG. 1a is an exploded perspective view of the conventional camera module, and FIG. 1b is a vertical sectional view of the conventional camera module. As shown in the drawings, the lens part 110 includes a lens. 112, a barrel for accommodating the lens 112, and a cap 116 provided in the upper outer circumference of the barrel 114 and having an incident hole formed at the center thereof.
Meanwhile, at least one lens 112 may be installed in the barrel 114 according to function and performance of the camera module to be implemented.
The housing 122 has an inner hole 124 for accommodating the barrel 114. The inner hole 124 is coupled with the barrel 114 such that the lens part 110 and the housing 122 are coupled with each other. The barrel 114 has a male thread 114a formed in the outer circumference thereof and the inner hole 124 has a female thread 124a formed in the inner circumference thereof so that the male thread 114a is coupled with the female thread 124a, whereby the barrel 114 is movably installed in the housing 122 having a fixed position.
Meanwhile, the sensor part 130 is fixed in the housing 122. The sensor part 130 converts an image of an object being incident through the lens 130 into an electric signal to form an image.
To this end, the sensor part 130 includes an image sensor 132, the IR filter 134, and a substrate 136. The image of the object passes through the lens 130 is partially filtered by the IR filter 134 and is detected by the image sensor 132.
Moreover, since the image sensor 132 is electrically connected to the substrate 136, that is, an image transmission device such as a flexible printed circuit board (FPCB), the image of the object detected by the image sensor 132 is converted into an electric signal by the image sensor 132 and is transmitted to the substrate 136, then a display. (not shown) such as a liquid crystal display (LCD) forms the image on a screen.
Not described reference numeral 119 of FIG. 1b is assigned to a spacer for maintaining a gap between the lenses 112 accommodated in the barrel 114, and reference numeral 139 is assigned to an adhesive resin for fixing the IR filter 134.
Moreover, a barrel 114′ having a male tread to couple the barrel 114′ to the housing 122, as shown in FIG. 2, may be coupled with a cap 116′ screwed to the lower side thereof such that the barrel 114′ fixes the spacer 119 accommodated in the barrel 114 and associated with the lenses 112′.
However, since the barrels 114 and 114′ and the housing 122 employed in the conventional camera module should be manufactured by separate molds due to the fact that the structure of the barrels 114 and 114′ to accommodate the lenses 112 and 112′ must be screwed to the housing 122, it takes a long time to design a new product and manufacturing costs and material costs are increased so that the camera module as a product loses competitiveness in view of costs and a limit to reduce its size.
There occurs deterioration of resolution, tilt, looseness or tightness according to the assembled state of the barrels 114 and 114′ and the housing 122 with bolts because of the shape fitting problem of the barrels 114 and 114′ and the housing 122 being manufactured by separate molds. Moreover, it takes a long time to assemble the barrels 114 and 114′ with the housing 122 because of the small size of the lenses and the spacer assembled in the barrels 114 and 114′ so that workability for the assembly is deteriorated.
Moreover, the housing 122 coupled with the barrels 114 and 114′ is mounted on the substrate 136 having the image sensor 132 after installing the IR filter 134 to the lower side of the housing 122 or on the substrate 136 having the image sensor 132 on which the IR filter 134 is attached.
When the assembly of the housing 122 and the substrate 136 is finished, there are performed a series of processes including a focusing process of adjusting the focusing distance between the lenses 112 and 112′ and the image sensor 132 with a naked eye or a software to optimize the focusing, a marking process of marking the optimal focus after the focusing process, a bonding process of coating UV bond on the cap 116, and a hardening process of hardening the coated UV bond using ultraviolet rays, that are required in assembling a focused camera module.
However, since a worker manually moves the barrels 114 and 114′ screwed to the housing 122 to adjust the focus, there occurs a focusing difference of 20 μm to 30 μm according to the worker's skill. Due to distortion of the lenses arranged in the barrels during the marking process, there occurs a focusing difference of 10 μm to 20 μm, and there occurs a focusing difference of 20 μm to 30 μm due to the distortion of the lenses during the bonding process and the hardening process. Due to these focusing differences the resolution is deteriorated so that the reliability of the product decreases.
Particularly, when there is error in the focusing process, the resolution of the camera module deteriorates, and since it takes a long time to assemble and complete the camera module due to a complicated assembling process, the productivity is decreased.
Further, since the male threads 114a and 114a′ of the barrels 114 and 114′ and the female thread 124a of the housing 122 are fastened with each other, when foreign matter remaining in the male threads 114a and the 114a′ or the female thread 124a drops down on the IR filter 134, the foreign matter covers pixels of the image sensor when the image of the object is displayed so that a black spot appears on a screen in the image where the image is displayed. Thus, the reliability of the product is deteriorated.